Construction of a novel water quality index and quality indicator for reservoir water quality evaluation: A case study in the Amazon region

- A novel water quality indicator and water quality index were created.
- Factor analyses and quality curves were created for the relevant parameters.
- Both indices were applied at a Hydroelectric Power Plant reservoir in the Amazon.
- The indices indicate that the hydrological cycle affects reservoir water quality.
- The WQI was also useful in identifying anthropogenic impacts in the area.

SummaryA novel Quality Indicator (QI) and Water Quality Index (WQI) were constructed in the present study for the evaluation of the water quality of a Hydroelectric Plant reservoir in the Amazon area, Brazil, taking into account the specific characteristics of the Amazon area. Factor analyses were applied in order to select the relevant parameters to be included in the construction of both indices. Quality curves for each selected parameter were then created and the constructed QI and WQI were then applied to investigate the water quality at the reservoir. The hydrological cycle was shown by the indices to directly affect reservoir water quality, and the WQI was further useful in identifying anthropogenic impacts in the area, since water sampling stations suffering different anthropogenic impacts were categorized differently, with poorer water quality, than stations near the dam and the environmental preservation area, which suffer significantly less anthropogenic impacts, and were categorized as presenting better water quality. The constructed indices are thus helpful in investigating environmental conditions in areas that show well-defined hydrological cycles, in addition to being valuable tools in the detection of anthropogenic impacts. The statistical techniques applied in the construction of these indices may also be used to construct other indices in different geographical areas, taking into account the specificities for each area.